Correlates of Canada Lynx Reproductive Success in Northwestern Montana

Habitat loss and fragmentation continue to threaten the persistence of forest carnivores in the contiguous US. The recovery of federally threatened species, such as the Canada lynx (Lynx canadensis), will be greatly enhanced by identifying a demographic-based definition of lynx habitat based on habitat analyses of animals with differential reproductive success. We collected field data on denning and offspring survival in northwestern Montana from 1998–2012. We used these data to define four response variables as measures of female Canada lynx reproductive success: (1) potential reproductive events, (2) initial litter size, (3) litter success (≥1 survivor), and (4) surviving litter size. We used mixed models to evaluate the effects of habitat and maternal condition on these response variables. Specifically, we tested a-priori hypotheses of relationships between reproductive success parameters and various habitat covariates representing the abundance and spatial configuration of five simplified forest structure types within occupied female lynx home ranges. Additional a-priori hypotheses were tested on the relationships between reproductive success parameters and maternal covariates, including female body condition, age, and previous reproductive performance. The most important predictors for overall lynx reproductive success within occupied female home ranges were the connectivity of mature forest, intermediate (10–15%) amounts of young regenerating forest, young regenerating forest patches with low perimeter-area ratios, and the adjacency of mature forest to young regenerating forest types. Female lynx home ranges that contain greater than 50% mature forest and approximately 10–15% young regenerating forest appear to be the optimal composition of forest structure types. Additionally, greater connectivity of mature forest, when combined with young regenerating forest patches with low perimeter-area ratios, appears to be the optimal configuration of forest structure types. Incorporating these results into current and long-term land management plans will provide a valuable conservation tool to ensure the persistence of threatened Canada lynx populations in the western US